Black-Tailed Prairie Dog Abundance and Distribution in the Great Plains Based on Historic and Contemporary Information
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University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Great Plains Research: A Journal of Natural and Social Sciences Great Plains Studies, Center for Fall 2002 Black-Tailed Prairie Dog Abundance and Distribution in the Great Plains Based on Historic and Contemporary Information Craig Knowles FaunaWest Wildlife Consultant Jonathan Proctor Predator Conservation Alliance Steven Forest Bozeman, MT Follow this and additional works at: https://digitalcommons.unl.edu/greatplainsresearch Part of the Other International and Area Studies Commons Knowles, Craig; Proctor, Jonathan; and Forest, Steven, "Black-Tailed Prairie Dog Abundance and Distribution in the Great Plains Based on Historic and Contemporary Information" (2002). Great Plains Research: A Journal of Natural and Social Sciences. 608. https://digitalcommons.unl.edu/greatplainsresearch/608 This Article is brought to you for free and open access by the Great Plains Studies, Center for at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Great Plains Research: A Journal of Natural and Social Sciences by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Great Plains Research 12 (Fall 2002): 219-54 © Copyright by the Center for Great Plains Studies BLACK-TAILED PRAIRIE DOG ABUNDANCE AND DISTRIBUTION IN THE GREAT PLAINS BASED ON HISTORIC AND CONTEMPORARY INFORMATION Craig J. Knowles FaunaWest Wildlife Consultant P.D. Box 113 Boulder, MT 59632 [email protected] Jonathan D. Proctor Predator Conservation Alliance 2260 Baseline Road, Suite 205-£ Boulder, CO 80302 and Steven C. Forrest 9443 Cottonwood Rd Bozeman. MT 59718 ABSTRACT-Recorded presettlement observations of black-tailed prairie dogs (Cynomys ludovicianus) are not adequate to fully determine their abundance and distribution. Early naturalists and explorers made only casual reports of prairie dogs on an opportunistic basis; their written records do not represent systematic surveys. Cumulative accounts of prairie dog control efforts, together with the known current prairie dog distribution in North Dakota and Montana, clearly show that most jour nalists failed to record prairie dog colonies. Also, they restricted their travels to a few common routes, and as a result only a very small and select portion of the landscape was surveyed. The hypothesis that prairie dogs dramatically increased in abundance following settlement is highly speculative. It ignores the fact that the Great Plains were once populated by large numbers of native ungulates, and that prairie dog control efforts began as early as the 1880s. Many lines of evidence suggest that the black-tailed prairie dog was common prior to European-American settle ment and occupied 2%-15% of large landscapes (400,000 ha or more). There are systematic accounts of prairie dogs at the time of settlement, government records concerning poisoning efforts, physical evidence of abandoned historic colonies, and contemporary information on prairie 219 220 Great Plains Research Vol. 12 No.2, 2002 dog ecology, dispersal, distribution, and abundance, as well as pre settlement accounts of large colonies measured in miles. The associa tion of an obligate predator (the black-footed ferret [Mus tela nigripes]) and a commensal bird species (e.g., mountain plover [Charadrius montanus 1 and burrowing owl [Athene cunicularia]) with the prairie dog (Cynomys spp.) is considered additional evidence that prairie dogs were abundant and widespread for an extended period. The presence of black tailed prairie dogs throughout the short- and mixed-grass regions of the Great Plains from southern Canada to northern Mexico provided an important and unique habitat to a variety of wildlife species. We con clude that the black-tailed prairie dog was more abundant than suggested by tallies of observations in the journals of early European travelers. KEY WORDS: black-tailed prairie dog, historic abundance Introduction The ecological importance of the black-tailed prairie dog (Cynomys ludovicianus) was not fully appreciated until the latter half of the 20th century, well after implementation of massive governmental eradication efforts. Early pleas to conserve small areas of prairie dogs for black-footed ferrets were largely ignored (Murie 1937). Apparently even professional wildlife biologists did not understand the importance of expansive, closely spaced prairie dog colonies to assure viable populations of associated spe cies. However, prairie dogs were and still are commonly viewed by farmers and ranchers as destroyers of the range and competitors of domestic live stock for limited forage resources, and as such should be eradicated or severely controlled. Private landowners' negative view of prairie dogs has resulted in a pattern on the landscape of small, widely spaced colonies interspersed by areas of local extirpation. This pattern developed in the early 1900s under government-sponsored poisoning campaigns, and it has been maintained by periodic bouts of poisoning. As a result of private landowners' dislike of prairie dogs, state laws have designated prairie dogs as a pest species, and state and federal conservation agencies have aided and abetted prairie dog control. At the behest of private landowners, state wild life management agencies have, for the most part, abdicated the authority to manage prairie dogs. Continuing population declines resulting from sylvatic plague, poi soning, habitat loss, and shooting led to a petition to list the black-tailed prairie dog as a threatened species under the Endangered Species Act in July 1998. In February 2000 the US Fish and Wildlife Service ruled that listing Black-tailed Prairie Dog Abundance and Distribution 221 the prairie dog was warranted, but it was precluded from doing so by a backlog of other species with higher listing priorities. The Fish and Wildlife Service evaluated the petition on the basis of these five listing criteria, as required by law: (l) present or threatened destruction, modification, or curtailment of habitat, (2) overutilization for commercial, recreational, sci entific, or educational purposes, (3) disease or predation, (4) the inadequacy of existing regulatory mechanisms, and (5) other natural or manmade fac tors affecting its continued existence (US Fish and Wildlife Service 1980). Pre settlement abundance and distribution of prairie dogs was not a factor in the listing assessment. The Fish and Wildlife Service determined that (1) a significant portion of prairie dog habitat had been permanently lost to agricultural conversion of grasslands, (2) recreational shooting of prairie dogs is an unregulated and common practice, (3) sylvatic plague has im pacted prairie dog numbers over a significant portion of its range, (4) state laws classify prairie dogs as a pest species and promote prairie dog control, and (5) prairie dog poisoning remains a common management practice (US Fish and Wildlife Service 2000). In its report the Fish and Wildlife Service noted that the black-tailed prairie dog is a colonial species, and that many remaining colonies throughout much of the range are small and isolated. Consequently, eradication of colonies through control efforts, plague, habi tat loss, and other impacts over time may lead sequentially to local extirpa tions and range contractions. Since prairie dogs are a highly colonial species, the reduction in size and number of colonies represents a reduction in distribution, even though the geographic distribution has not decreased proportionately to the reduction in numbers. Although the black-tailed prairie dog still occurs over a vast region and numbers in the millions, its colonial characteristics make it vulnerable to impacts identified in the five listing criteria. Virchow and Hygnstrom (2002) challenge the Fish and Wildlife Service's decision that the black-tailed prairie dog warrants listing; they suggest that presettlement distribution and abundance of the black-tailed prairie dog were not carefully considered. In their analysis, little evidence exists to suggest that black-tailed prairie dogs were historically "superabun dant" in the Great Plains. Although presettlement abundance and distribu tion are not part of the listing criteria, both past and present prairie dog distribution and abundance is an important issue that needs to be addressed. Evidence suggests that the black-tailed prairie dog was once significantly more common in the Great Plains than it is today. We define "common" as occupying 2%-15% or more of large landscapes (400,000 ha or more). This would represent local popUlations of 200,000 to 1,000,000+ individual 222 Great Plains Research Vol. 12 No.2, 2002 prairie dogs. In this paper, we examine historical and biological literature regarding prairie dog distribution and abundance. In particular, we focus on evidence from the northern Great Plains, where domestic livestock were not introduced until the late 19th century and widespread homesteading was not initiated until the early 20th century (Howard 1959). We conclude that black-tailed prairie dogs were very common and widespread in this area and that within this region prairie dogs have been greatly reduced from their original abundance. As evidence, we cite (1) the habitats prairie dogs cur rently occupy and the availability of such habitat; (2) the number, distribu tion, and size of extant prairie dog colonies; (3) the ability of prairie dog colonies to expand into suitable habitats; (4) the dispersal abilities of prairie